Front brake rotor/hub heat insulator/isolator.

[69427]

While waiting around for the weather to warm up so I can get back to working on improving the idle quality of my antique, my mind wandered to a short project to do in the meantime. I'm thinking on making a couple .040" titanium or stainless (whichever machines easier) rings to insert between the rotor hat and the spindle hub, in an effort to reduce the heat transfer from the hat into the (C4) spindle bearings. This obviously isn't a perfect heat isolator, but it should be directionally correct to make life easier on the bearings.

I'm going back and forth with the idea of putting similar rings between the rotor hat outer and wheel inner surfaces. Not as important as above on my list at the moment, and I need to first see how much of a PITA these rings are to fabricate.

 

[phantomjock]

Sounds like you are looking for Very Thin wheel spacers. Just a different position--between the hat and the hub, vice the hat and the wheel.
A bit thicker - but you could try some thin spacers ~ 0.25 maybe 0.125 to test the idea? Might need to trim the overall diameter.

OR - What about just using a set of 5 (each wheel) wave (spring) washers. Blank space = no direct conduction of heat. Just convection. 080 compress to 040.
McMaster


Cheers - Jim

 

[BBShark]

These might work.

 

[69427]

I appreciate the input, guys. Insulating/spacing the five areas at the lug studs would thermally be the best solution, and I can't post a definitive law of physics argument against it, but as only an electrical engineer and not a mechanical/structural engineer, I've been defaulting towards a conservative ring shape at the moment. Given the rotor hat material (aluminum), high shear forces (albeit limited in possible angular distance) between the rotor hat and the hub, along with the lateral forces and multiple temperature gradients at the hat/wheel bolt circle, I'll openly admit I'm just winging it and basing my decision on my comfort level.

 

[rtj]

Ducting in cooling air would be more effective than thin metal shims.

 

[rtj]

Or, get some old aluminum c3 mag wheels and carve air pumps in them. . Kind of like the bbs wheel fans or c4 rims.

 

[69427]

Ducting in cooling air would be more effective than thin metal shims.

I agree. But remember, thin titanium is more than a shim, it is a significant thermal impedance between two objects.
The shims are an additional effort to keep the wheel bearings alive during track days. My front spoiler lower section is shaped to direct air to the lower control arm area, and deflectors installed on the lower control arms then direct the air to the bearings/rotor-center for cooling (cooling hoses won't package well with my setup). While functional, I wasn't totally happy with the deflectors as they look kinda shade-tree-mechanic style, but years later I saw that the C6Z(?) had similar deflectors on their LCAs, so I quit losing sleep about the aesthetics of my deflectors.